1. Field of the Invention
The present invention relates to a calibration method and electronic device, and more particularly, to a calibration method and electronic device calibrating a simulated motion trace by vector transformation.
2. Description of the Prior Art
With advances of micro electro mechanical systems (MEMS), accelerometers or G-sensors are embedded in various sports equipments to record usage data of athletes, which can be utilized for analyzing athletic skills. For example, a baseball bat or a golf club is embedded with an accelerometer to record data of a bat swing or a club swing, which is further analyzed and simulated by a computer and displayed on a screen. As a result, the athletes can repeatedly watch the bat swing or club swing to improve athletic skills.
Please refer to FIG. 1A, which is a schematic diagram of a simulated golf swing trace 10 of the prior art. In order to simulate the golf swing trace 10, acceleration data recorded by an accelerometer embedded in a head 110 of a golf club 100 are required. In addition to the acceleration data, inclination angle data recorded by the accelerometer are also required to correctly simulate the golf swing trace 10. If the inclination angle data are incorrect, a simulated golf swing trace 12 will be rotated as illustrated FIG. 1B, and is difficult for watch.
In fact, the inclination angle data relate to an installation angle of the accelerometer in the head 110, as illustrated in FIG. 1C. In FIG. 1C, an accelerometer 120 is screwed into the head 110 and then fixed by a thread or adhesive. However, due to technical limitation, a manufacturer cannot guarantee that the accelerometer 120 is installed in the same position for each sports equipment, such that the recorded inclination angle is biased.
Therefore, before delivery to retail stores, the manufacturer has to calibrate the position of accelerometer 120 for each sports equipment to minimize the inclination angle error. In addition to the initial calibration, the accelerometer 120 will loose and drift from the initial installation position after intense club swing, and therefore has to be regularly calibrated, which is troublesome to both of the manufacturer and the user.
Accordingly, the industry focuses on reducing the interference caused by the positional error of the accelerometer for motion trace simulation.